The A-Z Plant Health Handbook for New Zealand,
by Jon Muller.
4. KEY TO PROBLEMS
This section deals with how to solve plant problems using the pest, disease
or disorder as the key rather than the plant. It summarises the plants
that are affected by the problem, symptoms and the control methods, including
cultural, alternative and chemical. These methods are usually identical
for the same pest, disease or disorder, so a summary is ideal for quick
reference. The suggested chemicals listed under control methods include
all those mentioned in the main section of the book. As well as providing
a summary, it also gives a wider selection of chemicals to choose from.
The first two pages are reproduced here. For the
full list of problems included in The A-Z Plant Health Handbook see
below.
Aphid
|
Symptoms: Small soft-bodied insects are found on the growing
tips of the plant. Leaf curling, stunting, wilting, distortion and
sooty mould growth may occur. |
Plants affected: delphinium, fuchsia, oak, orchid, peach,
rose, silver birch |
Control methods
Cultural: Check your watering, as drought stress can make the
plant more susceptible. Apply mulch.
Alternative: Use neem oil, garlic or onion/garlic, pyrethrum
or soapy sprays. Attach yellow sticky traps.
Hose off insects or squash them with your fingers.
Nasturtiums planted nearby will lure away aphids.
Suitable plants to attract predators and parasites include blue tansy,
coriander, cosmos, lavender, sunflower, and yarrow.
Avoiding chemicals may encourage parasites and predators.
Chemical: Use Confidor, Maldison, Mavrik, Supershield or Target
insecticide.
On larger trees control may not be practical. |
Apple leaf curling midge
(Similarly, pear leaf-curling midge) |
Symptoms: Leaves become curled and distorted. Pink maggots
can be found inside |
Plants affected: apple (pear) |
Control methods
Cultural: Cultivate under trees in winter to kill pupae.
Younger trees are more prone to attack or damage.
Chemical: Younger trees can have liquid Diazinon applied at
the first signs of midge infestation. |
Armillaria
|
Symptoms: The plant shows poor growth, branches die back,
and the tree eventually dies.
Dark honey-coloured mushrooms can appear on the stumps and trunks
of
infected trees in autumn and winter. Black cord-like structures known
as
rhizomorphs appear under the bark of infected trees. |
Plants affected: fivefinger, kiwifruit, willow |
Control methods
Cultural: Remove old stumps and roots from the ground before
replanting.
Maintain ideal growing conditions in surrounding uninfected plants.
Alternative: Apply Trichopel to roots. |
Bacterial blast
|
Symptoms: Die-back on branches occurs, with stem cankers.
|
Plants affected: cherry |
Control methods
Cultural: Prune out infected branches below areas that have the disease.
Chemical: Apply copper oxychloride. |
Black spot
|
Symptoms: Black spots appear on leaves as well as fruit.
|
Plants affected: apple, rose |
Control methods
Cultural: Remove and destroy all infected leaves and fruit,
rather than put them in compost.
Alternative: Plant chives close to roots.
Chemical: Apply copper oxychloride during winter and before
leaf burst.
Apply Greenguard, Guardall, Saprol or Supershield regularly over the
growing season. |
The full list of problems included in The
A-Z Plant Health Handbook
|
|
Aphid
Apple leaf-curling midge
Armillaria
Bacterial blast
Black spot
Bladder plum
Blight
Botrytis
Brown rot
Bulb fly
Bulb mite
Canker
Caterpillar
Citrus red mite
Clematis wilt
Codling-moth
Die back of lacebarks
Downy mildew
Dry conditions or drying winds
Dutch elm disease
Earwig or katydid
Eriophyid mite
Excessive humidity
|
Fairy rings
Fire-blight
Frost damage
Fusarium patch
Galls
Gall midges
Grass grub
Grease spot
Irregular watering
Leaf curl
Leafhopper
Leaf miner
Leaf rollers, webbers & tiers
Leaf spots
Lemon tree borer
Lime-induced chlorosis
Magnesium deficiency
Mealy bug
Moss in lawns
Nematode
Nitrogen deficiency
Passionvine hopper
Pear leaf blister mite
|
Pear & cherry slug
Phosphorus toxicity
Phytophthora wilt
Porina
Phylloxera aphid
Powdery mildew
Psyllid
Raspberry bud moth
Red thread
Root rot fungi
Rust
Scale insect
Sclerotinia
Silver leaf
Slugs & snails
Spider mite
Stem rot
Thrips
Verrucosis
Virus
Wind damage
Woodiness in stems or fruit
|
|
Excerpts
Looking after Roses & Camellias
List of plants included
Key to problems
Causes & Solutions
Guide to Chemicals
&
Alternatives to Chemicals
Introduction
Table of Contents
Links
Buy books
Acknowledgement
|
